Underwater drilling apparatus



Jan. 13,1970 c. E. WAKEFIELD, JR 3,489,210

UNDERWATER DRILLING APPARATUS 3 Sheets-Sheet 1 Filed Jan. 13, 1967 nHnHnHaL kulillllll I -P IJlIlIIlilllll INVENTOR. CY-IAIQLES' E. M/(E/ZEZD, J5

1970 c. E. WAKEFIELD, JR 3, 8

UNDERWATER DRILLING APPARATUS Filed Jan. 13, 1967 3 Sheets-Sheet 2 (HA/P1615 a W/zkEF/E ,"J/e. Ffra 4.

ATTO/F/VE Jan. 13, 1970 c. E. WAKEFIELD, JR 3,489,210

UNDERWATER DRILLING APPARATUS 3 Sheets-Sheet 3 Filed Jan. 15, 1967 INVENTOR. (HA/Q4615 E. K444177510, J/FI United States Patent 3,489,210 UNDERWATER DRILLING APPARATUS Charles E. Wakefield, Jr., Long Beach, Calif., assignor to Atlantic Richfield Company, Philadelphia, Pa., a corporation of Pennsylvania Continuation-impart of application Ser. No. 454,019,

May 7, 1965. This application Jan. 13, 1967, Ser.

Int. Cl. E21b 33/035, 33/00 US. Cl. 166.5 7 Claims ABSTRACT OF THE DISCLOSURE My present invention is a continuation-in-part application of my copending application S.N. 454,019, filed May 7, 1965, now Patent No. 3,398,790 and relates to offshore drilling and production apparatus for operations on a well underlying a body of water. More particularly my present invention relates to an improved apparatus for facilitating installation of a production head remotely in a benthonic drilling mandrel after drilling operations have been conducted through the drilling mandrel from a drilling structure on the body of water. The aforementioned parent application discloses a method for hanging the surface casing within a benthonic drilling mandrel to thereby obviate the need for round tripping the riser pipe in order to reattach the lower end of the riser pipe to the benthonic well head.

It is an object of the present invention to provide apparatus by which casing can be landed within the drilling mandrel on a casing hanger and the production mandrel subsequently landed on the drilling mandrel and sealingly engaged with the upper end of the surface pipe.

It is also an object of the present invention to provide a protective means for protecting the sealing surface of the upper end of the casing hanger hung in a benthonic drilling mandrel during well operations conducted before a production head is landed on the drilling mandrel in sealing engagement with the upper end of said casing hanger.

Other objects and a more complete understanding of my present invention may be had by reference to the following specification and the appended claims when taken in conjunction with the following drawings, wherein:

FIG. 1 shows schematically, in partial section, ocean floor drilling equipment utilized in my present invention with the surface pipe installed in a drilling mandrel, and

FIG. 2 shows the apparatus of FIG. 1 with additional casing hung within the surface pipe,

FIG. 3 is an enlarged sectional view showing a protective bushing in the upper end of the casing hanger,

FIG. 4 is an enlarged view taken on line 4-4 of FIG. 3 showing the inner surface of the protective bushing,

FIG. 5 is a section taken on line 5-5 of FIG. 3, and

FIG. 6 is an enlarged sectional view showing a bushing retrieving tool in position to remove the protective bushing from the casing hanger.

FIG. 7 shows a production head landed in the conductor mandrel with a drill pipe;

FIG. 8 shows blowout preventers and a riser installed on the production mandrel.

Referring briefly to the drawings, an apparatus is shown for drilling a well in a formation underlying a body of water from a drilling structure (not shown) located at the surface of said body of water, utilizing a drilling mandrel 12 into which a casing 24 attached to the lower end of a casing hanger 25 can be hung. A production mandrel 28 is subsequently installed in the drilling mandrel 12 (FIG. 7). In order to reduce the number of hanger packings that are exposed to well pressure the lower end of the production mandrel 28 is sealed into the upper inner surface of the casing hanger 25 at 27. In order to protect the sealing surface in the casing hanger 25 a protective bushing or bit guide 29 is provided as shown in FIGS. 1 and 2. Just before the production mandrel 28 is landed in the drilling mandrel 12, the bushing 29 is removed with a retrieving tool 60 as shown in FIG. 6.

Referring now more particularly to FIG. 1, a drilling mandrel 12 is installed on the upper end of a conductor pipe 10 and landed at an underwater formation 18 in a suitable seat provided in landing base 16. A surface pipe 20 is landed on a shoulder 22 in the drilling mandrel 12 with a surface pipe hanger 46. Casing 24 is then hung on a shoulder within the surface pipe hanger 48 with any appropriate casing hanger means such as the casing hanger arrangement shown in Patent No. 3,279,539 issued to C. C. Brown et al. The upper end of the casing hanger 25 extends upwardly. The inner surface of the upper extension is protected against damage which may occur during drilling and subsequent operations prior to landing the production mandrel, by a protective bushing or bit guide 29 which is shear-pinned to the casing hanger 25 before the casing hanger is lowered from a drilling structure such as a floating vessel, located at the surface of the water. Drilling operations may be conducted through the apparatus shown in FIG. 1 from the structure through a riser pipe 30 which is connected to the upper end of a blowout preventer stack 36 which in turn is latched to latching neck 32 of the upper end of the drilling mandrel 12 with a conventional latch mechanism 34. In FIG. 2 an additional casing 26 is installed within the casing 24 on a shoulder therein.

FIG. 3 is an enlarged view of the upper end of the casing hanger 29, showing the protective bushing 29. FIG. 5 best shows the manner in which the bushing 29 is connected to the casing hanger 25. Shear pins 31 are provided through mating holes in the bushing 29 and the casing hanger 25. Lugs 33 are provided on the bushing to fit into corresponding slots 35 of the casing hanger. The engagement of the lugs 33 in the slots 35 prevents rotation of the bushing within the casing hanger during the drilling operations.

After the drilling operations have been completed and the inner casing 26 installed, the protective bushing 29 is removed with a retrieving tool 60 which is threadably attached to drill pipe 62. The retrieving tool 60 is run down through riser pipe 30 and into the drilling mandrel 12 and bushing 29, with the lugs 64 of the retrieving tool passing down longitudinal slots 66 in the bushing. When the retrieving tool is set down into the bushing 29, the lugs 64 of the retrieving tool are in the position shown at 64a in FIG. 4. The retrieving tool is then turned to the right by rotating the drill pipe to the right and the drill pipe picked up to move the lug 64 to the position 64b shown in FIG. 4. Further lifting the retrieving tool shears the pins 31 and removes the protective bushing 29 to the structure.

With the protective bushing 29, the riser 30, and the blowout preventer stack 36 removed, the production mandrel 28 can be lowered from the structure on a running tool 45 with a drill pipe 37 having a stinger 39 thereon which serves to maintain contact with the well when the drill pipe is raised to the drilling structure. The production mandrel 28 is latched into the drilling mandrel with a suitable remote connector, for example, the connector shown and described in copending application of C. C. Brown, S.N. 456,968, filed May 19, 1965. The lower end of the production mandrel 28 is sealed into the upper end of the casing hanger 25 as heretofore mentioned. This seal between the upper end of the casing hanger 25 and the lower end of the production mandrel 28 aids in keeping the well zone pressures off of the large casing hanger packings in the drilling mandrel and thus reduces the number of hanger packings that are exposed to well pressure. After the production mandrel 28 is connected into the drilling mandrel 12 as shown in FIG. 7, the riser and blowout preventer stack 36 may be reconnected to the upper end of the production mandrel as shown in FIG. 8.

While the apparatus of my present invention has been described herein with a certain degree of particularly, it is to be understood that the scope of my invention should not be limited to the details set forth, but be afforded the full breadth of the appended claims.

I claim:

1. A method for drilling a well in a formation underlying a body of water from a drilling structure through a casing riser alfixed to the upper end of a drilling mandrel, consisting essentially of the following steps:

landing said drilling mandrel in said well,

drilling said well from said structure through said riser sufficiently deep to receive a casing,

lowering a casing through said riser into said well, said casing having a hanger on the upper end thereof for hanging said casing in said drilling mandrel, with a protective bushing temporarly affixed inside the upper end of said hanger, conducting drilling operations from said structure through said casing,

removing said protective bushing from the upper end of said casing hanger to said structure,

landing a production head on said drilling mandrel and in abutting relationship therewith with the lower end of said protection head sealingly engaging the upper inner surface of said casing hanger, and

hanging production tubing in said well from said production head.

2. The method of claim 1 wherein an additional casing is hung within said casing hanger before said protective bushing is removed therefrom.

3. An apparatus for drilling and producing a well in a formation underlying a body of water from a drilling structure comprising:

an aperture well base positioned at the well opening,

a drilling and production mandrel landed at said well opening in said well base aperture,

a casing hanger hung within said mandrel,

a protective bushing temporarily affixed to the upper end of said casing hanger to protect a portion of the inner surface of said casing hanger during working operations conducted through said casing hanger.

a production mandrel arranged and constructed to land within and in abutting relationship with, the upper end of said drilling mandrel with the lower outer surfaces of said production mandrel sealingly engaging the upper inner surface of said casing hanger after said protective bushing is removed from said casing hanger, and

means for hanging production tubing in said well from said production mandrel.

4. The apparatus of claim 3 including means for remotely removing said protective bushing from said casing hanger prior to the landing of said production mandrel.

5. The apparatus of claim 3 wherein said protective bushing is shear-pinned to said casing hanger.

6. The apparatus of claim 3 including means for preventing rotation of said bushing with said casing hanger.

7. An apparatus for drilling and producing a well in a formation underlying a body of water from a drilling structure, comprising in combination:

a drilling mandrel adapted to be set on the ocean floor,

means for hanging casings within said drilling mandrel,

means for protecting a sealing surface of one of said casings during drilling operations subsequent to hanging said one casing in said drilling mandrel, means for remotely removing said protecting means from said casing, means for connecting a production mandrel in and to said drilling mandrel above said casing hangers whereby the lower end of said production mandrel seals into said protected inner sealing surface of said casing, and means for hanging a tubing string in said production mandrel.

References Cited UNITED STATES PATENTS 3,064,735 11/1962 Bauer et a1. 166-.6 3,137,348 6/1964 Ahlstone et a1. 166-.6 3,163,220 12/1964 Haeber et a1 -7 X 3,227,229 1/1966 Wakefield 166-75 X 3,239,248 3/1966 Jones 166-88 X 3,247,914 4/1966 Slack 166-88 X 3,256,937 6/1966 Haeber et al 166-.6

CHARLES E. OCONNELL, Primary Examiner RICHARD E. FAVREAU, Assistant Examiner 

